Everybody talks about it in general but when does a engine overheat...is there a critical degree which should be avoided??

Should coolanantifreeze be used year round?

Because I know how these motors are built, anything above 210 would give me the chills on an 8.2L.

Reason I'm quoting low is you still need time to pull off the road and shut it off.

If it goes above 230 - you've got a boat anchor on your hands.

Do Not Ever Overheat An 8.2L Detroit Engine!!!
Never Open Up A Radiator Cap That Is Hot!!!

If I owned an 8.2L I would be driving with one eye on the temp gauge. I would have a warning alarm at 210 and a low coolant alarm installed.

Every truck mfg has these devices installed on their trucks, most are programmed to shut the engine off automatically if it goes out of range.

OK...what else can one do??

Seeing that it is the engine that is installed I can't change that so ???? How did they last for 30 years if they are so bad??? Are there any upgrades or DIY improvements?

If you think of the physics involved, the engine was designed to keep itself under the critical temperatures if everything is in design parameters. The problem with any machine is that things wear out, break, clog up, etc.

Your cooling system has coolant, a water pump (as well as whatever drives it), a radiator and a thermostat that all work together to keep the engine both cool enough and warm enough. If all these items are in top shape you could expect the engine will keep itself in operating range under normal driving conditions.

What are "not so normal driving conditions" then? Towing, climbing tall mountains, altitude (the air is thinner restricting heat transfer), running too low an RPM (water pump may not be circulating enough), and high ambient temperatures that lower the heat transfer from the radiator.

RVs and buses are particularly difficult to cool with rear engines due to the desire to place the radiator in the rear near the engine. Unlike front engine set-ups, where the radiator is right out in the open air, rear mounted radiators must pull the air forcibly into the radiator as they are either rear or side mounted in the slipstream of the body. Another problem in this design is strong cross winds that restrict the fan's ability.

What can be done to improve cooling? Well, you could build giant scoops that drive air into the radiator, but you'd suffer poor fuel mileage for this small improvement. The better way to view it, is what can be dome to keep the engine working as it was designed.

Two simple things (simple to say anyway); 1) keep all the mechanicals in top shape and 2) avoid situations described above that negatively affect cooling.

As Bill stated, also make sure you fail-safe warning systems are functional.

To answer your final question, YES, you should run the proper mix of anti-freeze year round. It really is improperly called anti-freeze, better called coolant.

A few more tips:
* Check your water pump belt
* check your water pump for excessive play in the bearing or leaking
* pressure check your cooling system
* monitor coolant level often
* inspect your radiator for blockage or corroded fins
* As previously suggested, view radiator's performance with IR camera/scope

An engine is like a pet, it will live a lot longer than average if well kept. An 8.2 may have inferior genetics, but a little luck and a lot of love will see it outlast many better bred designs.

....thanks for all the info!

would this product be of any use:

http://www.redlineoil.com/product.aspx?pid=75&pcid=10


Re: If it goes above 230 - you've got a boat anchor on your hands.

I have heard of a MCC boiling over while towing a Dussenberg on a trailer near MCR.

What happens/is destroyed in the process??

Doug, the 8.2 liter is prone to failure IF IT IS OVERHEATED... I can't state it enough. Do not overheat that engine!

Now, if the temp starts to climb, let off of the throttle. Keep looking at the readings. If you see it heat up, don't say to yourself that you only have a mile to go. These engines will not last if it ever overheats.

Put the better headbolts in if you want. The redesign for this engine took the 14mm headbolts up to 15mm.

If you say to yourself that the engine was put in there and it lasted 30 years so it'll be ok... then you're opening yourself up to all sorts of problems.

Does your coach have a new radiator? All new hoses? New waterpump? New thermostats? New belts? New fan clutch? Fresh coolant and recently flushed? See, some of these items are probably 30+ years old too. You didn't buy a new coach.

All I'm saying is you need to think about it before you blindly drive your coach. I can only arm you with the facts - I won't sugarcoat it. NEVER EVER OVERHEAT AN 8.2L DETROIT.

I will second the advice about not overheating the engine. My Detroit 8V71 is a great engine,....but overheating will kill it quickly. When i am going down the road i am keeping a close eye on the temp gauge, the tach, the oil pressure and last and least of all, the speedo. If i start to heat up it is usually because i have allowed the engine rpms to drop to low in whatever gear i am in. I have an auto tranny but i manually shift it 95% of the time. I also listen to the engine as i drive.....haven't listened to music in any of my rigs for probably 15 years or so. Several times that has alerted me to problems before they got worse, once was several lug nuts on my left front wheel that the tire shop hadn't properly torqued. Caught it before it did any damage to the wheel, or worse yet come off. Do all of my own wheels now. It was a very subtle noise that i picked up on, and my hearing isn't the best.

The two stroke Detroits are awesome engines, but also a good example of how the RV industry sometimes compromises compared to the bus lines. In a Prevost or MCI (bus chassis) equipped with a two stroke Detroit, there are giant bird-cage blowers that force fresh air down over the engine. This provides massive cooling as well as forcing road level dirty, hot air away from the engine. The problem with this design is the amount of space it takes up. A 45' Prevost has less interior space than my 43' Wanderlodge because of this design. You may already guess that the RV industry, when building their chassis, were very reluctant to give up this square footage. The result is an engine placement design that simply won't last as long as their over-road bus counterparts.

OK, What is to hot??

I was told by an engine engineer from DD that for the 71&92 series the danger point if vapor. As soon as you start making vapor you are in trouble. Vapor leaves some part of the engine exposed to very high temps and the diffent temps in the block/head will lead to uneven expansion and CRACK.

If you have a 50/50 mixture of coolant the the boiling point is close to 240 (don't remember exactly) and if you have a pressurized system it is higher than that. 180 degrees leaves a lot of fudge room.

I believe the same argument could be make about any engine be it diesel or gas.

quote:

I believe the same argument could be make about any engine be it diesel or gas.

I believe your right on the mark Gary.... I dont think the 8.2 is nessescarily more "prone" to overheating then any other engine regardless of type.... But is IS less "tolerent and forgiving" of that type of abuse....

quote:

Originally posted by Gary Carter:
I believe the same argument could be make about any engine be it diesel or gas.

quote:

Originally posted by Patch1st:
I believe your right on the mark Gary.... I dont think the 8.2 is nessescarily more "prone" to overheating then any other engine regardless of type.... But is IS less "tolerent and forgiving" of that type of abuse....

100% In Agreement. No argument there on either statement.

There are engine that can take a little bit of abuse when it comes to running hot - this one is NOT ONE that can tolerate ANY TYPE of overheating conditions.

If you overheat this engine - you will be replacing it - DO NOT run this engine hot.

When it comes to the 8.2 I would rather sound like the crazy guy in the room. Laugh if you want, but replacing a head gasket and actually getting it to reseal after it ran hot would be a miracle. These engines are unforgiving.

You can only overheat an 8.2 one time. After that, it usually becomes scrap iron.

With all the discussions about the disastrous results of overheating the 8.2, couldn't this problem be solved by simply installing an engine shut down that is activated at 210 degrees or some similar setting. I would think the cost of components would be less than $100.00, and as they say in the commercials "the cost of piece of mind-priceless".

Maybe I'm over simplifying the problem.

Nick

If your engine can shut down at 210, better have a warning buzzer at 200 that you can't ignore. I would personally prefer the buzzer for two reasons, 1) I think it would be dangerous to have it suddenly shut off with no warning, 2) it is not ideal to shut a hot engine off suddenly as the water pump and fan also shut down which can allow the engine to go much higher as the coolant stops moving.

If you know what's causing the high heat situation (as stated in a previous post) you are best off controlling the cool down. There is also the turbo to consider if so equipped.

quote:

Originally posted by Moonbeam-Express:
1) I think it would be dangerous to have it suddenly shut off with no warning, 2) it is not ideal to shut a hot engine off suddenly as the water pump and fan also shut down which can allow the engine to go much higher as the coolant stops moving.

Corey, I understand your points but my CAT 3208 300HP is equipped with an EPM (engine protection module) that will shut down the engine if any of the operating temperatures or pressures fall out of operating ranges. Coolant Temperature, Coolant Level, Oil Pressure, etc.

I guess they figured shutting it down was the better of bad alternatives.

Nick

I imagine my Detroit has something similar, but I hope it warns me on the way out of operating range.

Hope I never need to find out